As the brothers spoke to police afterwards, "one of the sons… stated that he had been planning this since he was eleven years old," according to a search warrant that was released on Monday and cited by the Atlanta Journal Constitution. It is not clear which brother made the claim.

The sons had reportedly called their parents to ask if they could make them dinner and police believe they then spiked the couple's drinks with Xanax. Yvonne was strangled and badly beaten, while Zachary was stabbed multiple times.

Following the attack, the sons admitted to "attempting to set the residence on fire, strangling their parents with a pillow and/or plastic bag, and stabbing the father," according to the search warrant.

Yvonne, 50, told the 911 operator: “They're trying to strangle and shoot us. They put Xanax in our food. They thought we were asleep and they tried to attack us. They beat me up. They beat him up. They're trying to kill us."